1. Field of the Invention
The present invention relates to a technique of transmitting image data.
2. Description of the Background Art
As one of conventional image processing apparatuses capable of performing communication through a network, an MFP (Multi Function Peripheral) is known. The MFP is a composite device having the functions of scanner, copier, printer, facsimile, and the like. Further, the MFP can attach an image read by the scanner function or the like to electronic mail (E-mail) and directly transmit the resultant to an MFP or the like at the destination via a network such as the Internet or a LAN.
In the case of transmitting E-mail from a transmission source to a destination, it is transmitted via a plurality of mail servers. In each mail server, a system administrator sets a size limit for E-mail. For example, when E-mail exceeding the size limit arrives, the E-mail may be rejected. Which one of the mail servers through which the E-mail passes rejects the E-mail is not determined.
The size of image data is increasing and, particularly, the size of color image data is enormous which is about 60 MB per image and may exceeds the size limit for E-mail set by a mail server. Consequently, an image to be transmitted is preliminarily divided by a transmission source so that the size does not exceed the size limit for E-mail, for example, 500K to 2 MB, each of the divided images is attached to E-mail, and the resultant is transmitted by divided mail to the destination.
The Internet is an infrastructure which does not guarantee data transmission to a destination and in which transmission data may be dropped out. There is consequently the possibility that any of the plurality divided mails to which the divided images are attached is not transmitted.
At the time of transmitting an image from a transmission source to a destination, generally, for example, when the page number of the image is associated with a management number of divided mail and it is determined that all of the divided mails are received by the destination, the image attached to all of the divided mails is printed/output. On completion of the printing/outputting, all of the divided mails are deleted. In such a manner, an error in E-mail transmission is detected. In the case of addressing the problem by the transmission source, all of the divided mails transmitted may be held for predetermined time.
However, some MFPs do not have a memory capacity sufficient to hold all of divided mails (image data) transmitted. In a general mail server, E-mail which is received by the transmission destination is deleted from the mail server.
Therefore, for example, when a unit image is divided into a plurality of images, a plurality of divided mails to which divided images are attached are transmitted, and even one of the divided mails is not delivered, if the MFP does not hold the transmitted image, the unit image has to be read again by the scanner function.
Although divided mails whose non-delivery notifications are not sent from the mail server may be sequentially deleted, if even one of the divided mails to which the divided images of the unit image is not delivered, the unit image has to be read by scanning. It is troublesome for the user to re-transmit the image by confirming a not-delivered unit image, setting the original, and the like.
Although image data is converted into a data format which can be attached to E-mail and the resultant data is attached to E-mail, even if the image data is stored, an image of the format attached to E-mail is held in a memory only at the time of transmitting the E-mail. Consequently, when the E-mail is not delivered, the format conversion has to be re-executed.